When IBM announced its acquisition of SPSS on July 28, 2009, the share price of SPSS common stock rose by 41 per cent in one day.

Martin, Conradt and Weishaus are accused of selling their SPSS positions for profits of $US7,900, $US2,538 and $US129,290 respectively.

Two others, who US authorities have codenamed CC-1 and CC-2, sold their SPSS positions for profits of $US629,954 and $US254,360 respectively.

Martin has been charged with one count of conspiracy to commit securities fraud and one count of securities fraud.

He was arrested in Hong Kong on December 22.

If convicted he faces up to 25 years' jail in the US and a $US5 million fine.

Martin, who moved to Hong Kong after the US Securities and Exchange Commission began an investigation into the matter, "knew that insider trading can result in jail sentences" and in one conversation with his IBM lawyer friend referred "to the criminal prosecution of (American business magnate) Martha Stewart", prosecutors alleged.

At a hearing in Manhattan three weeks ago, Conradt and Weishaus pleaded not guilty to conspiracy to commit securities fraud.